1. Field of the Invention
The present invention relates generally to blood glucose testing, and more particularly to a device which consistently wipes blood from a reagent strip, thus eliminating user variations and providing reliable test results.
2. Description of Related Art
Blood glucose testing is an important part of life for people afflicted with diabetes. Diabetics must monitor their blood glucose levels periodically to avoid complications caused by excessive levels of glucose in the blood. Although many diabetics received regular insulin injections which reduce the blood glucose level, blood glucose levels can still vary widely. The reason for this wide variation is that the regular insulin injections are not necessarily proportional to the blood glucose level. If a diabetic has ingested foods which raise the blood glucose level, the insulin present in his body may not be sufficient to return his blood glucose level to normal. Conversely, a diabetic may have a low blood glucose level caused by too much insulin in his system. Therefore, diabetics monitor their blood glucose levels periodically so that they may alter their ingestion of certain foods to either raise or lower their blood glucose level as needed. Sustained high or low levels of blood glucose may be an indication that the amount of insulin prescribed is either too low or too high, respectively.
Reagent strips are typically used to determine the blood glucose level in a sample of a diabetic's blood. The reagent strips are generally plastic strips which have a reagent pad on one end thereof. Chemicals on the reagent pad react with glucose to provide an indication of the concentration of glucose in the blood. The glucose in the blood sample causes the reagent pad to change color, and the resulting color is an indication of the concentration of glucose in the patient's blood. Typically, a sample of the diabetic's blood is placed on the reagent pad for a predetermined amount of time, and then the excess blood is wiped off to reveal the color of the reagent pad. The color of the reagent pad is then compared to a number of color standards which correspond to specific blood glucose level ranges. Alternatively, the reagent pads are inserted into a device, such a reflectance photometer, which more accurately determines the concentration of glucose in the blood sample on the reagent strip.
The accuracy of blood glucose testing of this type is affected by several factors. First, the blood sample should be left on the reagent pad for the predetermined amount of time. A longer or shorter time will affect the absorption of the blood into the reagent pad, and thus affect the resulting color of the reagent pad. Second, the wiping process which removes the blood after the predetermined amount of time can affect the resulting color of the reagent pad. If the method for wiping the blood off of the reagent pad is inconsistent, the blood glucose concentration indicated by the reagent pad will also be inconsistent. While the first problem can be substantially overcome by stressing the importance of accurately monitoring the amount of time that the blood sample remains on the reagent strip, the second problem can not be easily overcome merely through education of diabetic patients.
Current methods to remove the excess blood from the reagent strip include blotting or rubbing the reagent strip with tissues or another absorbent material while the reagent strip is place on a flat, hard surface. This method of blood removal requires a high degree of user technique and introduces a high level of user variability. Moreover, this type of blotting technique tends to smear or spread the blood.
In an attempt to produce consistent results and a controlled wiping action, Hyproguard LTD of Dock Lane, Woodbridge, Suffolk, U.K. is currently manufacturing a wiping device referred to as HY-GUARD. The HY-GUARD device is a disposable plastic device which accepts the blood sample into a capillary gap in the device which transports the blood to a reagent pad. Upon withdrawal, the reagent pad passes beneath an absorbent wiping material which removes excess blood from the reagent pad. While the HY-GUARD device provides consistent results as compared with the variability introduced by manual wiping, the absorbency of the wiping material can introduce inconsistencies during the wiping action. Moreover, the manufacture of the HY-GUARD device is complicated in that two molded parts must be assembled and the absorbent material must be attached thereto.